In aircraft, low detectability in relation to adversarial sensor systems is gaining increasing importance, particularly in the military sector, but also in civil aviation. The radar backscatter cross-section (RBCS) can be one important characteristic value for the detectability of an aircraft in that it constitutes a measure for the relationship of energy irradiated by a generic radar system to the energy reverberated or reflected back to the radar system. The RBCS depends strongly on the outer geometry of the aircraft. Accordingly, a substantial contribution to the RBCS can result from external loads attached to the aircraft, such as weapons, sensor containers and/or external tanks.
Particularly, the backscattering of an electromagnetic radar wave can be determined by two phenomena. From an electromagnetic perspective, an external load on an aircraft consists of the interaction of a supporting structure, also called a pylon, and the actual external load. A radar wave that strikes the aircraft can be reflected, on the one hand, directly on the external load and/or the pylon and be reflected back to the adversarial radar system, on the other hand, through multiple reflection with other structural components of the aircraft.
In order to reduce the RCBS-increasing effects of external loads, stealth aircraft often have weapons bays and/or payload containers in which weapons and/or other payloads can be carried along on the interior of the aircraft. In aircraft without a stealth geometry, however, such weapons bays and payload containers are usually not present and are also difficult to retrofit.